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NVVMIntrRange adds !range metadata to calls of NVVM intrinsics that return values within known limited range. This allows LLVM to generate optimal code for indexing arrays based on tid/ctaid which is a frequently used pattern in CUDA code. Differential Revision: http://reviews.llvm.org/D20644 llvm-svn: 270872
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| Original file line number | Diff line number | Diff line change |
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| //===- NVVMIntrRange.cpp - Set !range metadata for NVVM intrinsics --------===// | ||
| // | ||
| // The LLVM Compiler Infrastructure | ||
| // | ||
| // This file is distributed under the University of Illinois Open Source | ||
| // License. See LICENSE.TXT for details. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
| // | ||
| // This pass adds appropriate !range metadata for calls to NVVM | ||
| // intrinsics that return a limited range of values. | ||
| // | ||
| //===----------------------------------------------------------------------===// | ||
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| #include "NVPTX.h" | ||
| #include "llvm/IR/Constants.h" | ||
| #include "llvm/IR/InstIterator.h" | ||
| #include "llvm/IR/Intrinsics.h" | ||
| #include "llvm/IR/Instructions.h" | ||
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| using namespace llvm; | ||
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| #define DEBUG_TYPE "nvvm-intr-range" | ||
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| namespace llvm { void initializeNVVMIntrRangePass(PassRegistry &); } | ||
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| // Add !range metadata based on limits of given SM variant. | ||
| static cl::opt<unsigned> NVVMIntrRangeSM("nvvm-intr-range-sm", cl::init(20), | ||
| cl::Hidden, cl::desc("SM variant")); | ||
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| namespace { | ||
| class NVVMIntrRange : public FunctionPass { | ||
| private: | ||
| struct { | ||
| unsigned x, y, z; | ||
| } MaxBlockSize, MaxGridSize; | ||
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| public: | ||
| static char ID; | ||
| NVVMIntrRange() : NVVMIntrRange(NVVMIntrRangeSM) {} | ||
| NVVMIntrRange(unsigned int SmVersion) | ||
| : FunctionPass(ID), MaxBlockSize{1024, 1024, 64}, | ||
| MaxGridSize{SmVersion >= 30 ? 0x7fffffffu : 0xffffu, 0xffff, 0xffff} { | ||
| initializeNVVMIntrRangePass(*PassRegistry::getPassRegistry()); | ||
| } | ||
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| bool runOnFunction(Function &) override; | ||
| }; | ||
| } | ||
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| FunctionPass *llvm::createNVVMIntrRangePass(unsigned int SmVersion) { | ||
| return new NVVMIntrRange(SmVersion); | ||
| } | ||
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| char NVVMIntrRange::ID = 0; | ||
| INITIALIZE_PASS(NVVMIntrRange, "nvvm-intr-range", | ||
| "Add !range metadata to NVVM intrinsics.", false, false) | ||
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| // Adds the passed-in [Low,High) range information as metadata to the | ||
| // passed-in call instruction. | ||
| static bool addRangeMetadata(uint64_t Low, uint64_t High, CallInst *C) { | ||
| LLVMContext &Context = C->getParent()->getContext(); | ||
| IntegerType *Int32Ty = Type::getInt32Ty(Context); | ||
| Metadata *LowAndHigh[] = { | ||
| ConstantAsMetadata::get(ConstantInt::get(Int32Ty, Low)), | ||
| ConstantAsMetadata::get(ConstantInt::get(Int32Ty, High))}; | ||
| C->setMetadata(LLVMContext::MD_range, MDNode::get(Context, LowAndHigh)); | ||
| return true; | ||
| } | ||
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| bool NVVMIntrRange::runOnFunction(Function &F) { | ||
| // Go through the calls in this function. | ||
| bool Changed = false; | ||
| for (Instruction &I : instructions(F)) { | ||
| CallInst *Call = dyn_cast<CallInst>(&I); | ||
| if (!Call) | ||
| continue; | ||
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| if (Function *Callee = Call->getCalledFunction()) { | ||
| switch (Callee->getIntrinsicID()) { | ||
| // Index within block | ||
| case Intrinsic::ptx_read_tid_x: | ||
| case Intrinsic::nvvm_read_ptx_sreg_tid_x: | ||
| Changed |= addRangeMetadata(0, MaxBlockSize.x, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_tid_y: | ||
| case Intrinsic::nvvm_read_ptx_sreg_tid_y: | ||
| Changed |= addRangeMetadata(0, MaxBlockSize.y, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_tid_z: | ||
| case Intrinsic::nvvm_read_ptx_sreg_tid_z: | ||
| Changed |= addRangeMetadata(0, MaxBlockSize.z, Call); | ||
| break; | ||
|
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| // Block size | ||
| case Intrinsic::ptx_read_ntid_x: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ntid_x: | ||
| Changed |= addRangeMetadata(1, MaxBlockSize.x+1, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_ntid_y: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ntid_y: | ||
| Changed |= addRangeMetadata(1, MaxBlockSize.y+1, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_ntid_z: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ntid_z: | ||
| Changed |= addRangeMetadata(1, MaxBlockSize.z+1, Call); | ||
| break; | ||
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| // Index within grid | ||
| case Intrinsic::ptx_read_ctaid_x: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ctaid_x: | ||
| Changed |= addRangeMetadata(0, MaxGridSize.x, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_ctaid_y: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ctaid_y: | ||
| Changed |= addRangeMetadata(0, MaxGridSize.y, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_ctaid_z: | ||
| case Intrinsic::nvvm_read_ptx_sreg_ctaid_z: | ||
| Changed |= addRangeMetadata(0, MaxGridSize.z, Call); | ||
| break; | ||
|
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| // Grid size | ||
| case Intrinsic::ptx_read_nctaid_x: | ||
| case Intrinsic::nvvm_read_ptx_sreg_nctaid_x: | ||
| Changed |= addRangeMetadata(1, MaxGridSize.x+1, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_nctaid_y: | ||
| case Intrinsic::nvvm_read_ptx_sreg_nctaid_y: | ||
| Changed |= addRangeMetadata(1, MaxGridSize.y+1, Call); | ||
| break; | ||
| case Intrinsic::ptx_read_nctaid_z: | ||
| case Intrinsic::nvvm_read_ptx_sreg_nctaid_z: | ||
| Changed |= addRangeMetadata(1, MaxGridSize.z+1, Call); | ||
| break; | ||
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| // warp size is constant 32. | ||
| case Intrinsic::nvvm_read_ptx_sreg_warpsize: | ||
| Changed |= addRangeMetadata(32, 32+1, Call); | ||
| break; | ||
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| // Lane ID is [0..warpsize) | ||
| case Intrinsic::ptx_read_laneid: | ||
| Changed |= addRangeMetadata(0, 32, Call); | ||
| break; | ||
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| default: | ||
| break; | ||
| } | ||
| } | ||
| } | ||
|
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| return Changed; | ||
| } |
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